Agricultural round balers have been used for several decades to collect and bind crop material so as to facilitate the storage of crop material for later use. Generally, a mower or mower-conditioner cuts the crop and arranges it in a windrow for drying. Later, an agricultural tractor pulls a baler over the windrow to collect the crop material. The baler's windrow pickup gathers the cut and windrowed crop and lifts it into the baling chamber. The baling chamber consists of a pair of opposing sidewalls with a series of belts that rotate and compress the crop material into a cylindrically shaped bale. When the bale has achieved a desired size and density, the operator wraps the bale to ensure that the cylindrical and compact nature of the bale is maintained.
There are many wrapping materials and methods of wrapping the bale depending on a variety of factors. Initially, twine was used to wrap the bale. Later net wrap and silage sheets were introduced. Generally, these methods focused on covering the cylindrical portion of the bale and not the ends. After the bale is bound or wrapped, it is ejected from the baler for later pickup by the farmer.
As previously mentioned, there are a variety of agricultural round balers. A general example of this device is illustrated by the New Holland Roll-Belt TM Round Baler model number 678 manufactured by New Holland North America, Inc. Generally, round balers are pulled by an agricultural tractor and receive rotational power from the tractor's power-take-off shaft positioned at the rear of the tractor. The energy is transmitted to a gearbox positioned on the baler. Some balers also use a hydraulic motor and pump arrangement to provide energy to the various baler elements such as the various rollers and belts. As previously discussed, a variety of methods are used to wrap the bale. Relatively recently, the use of netting, herein termed netwrap, has been introduced. It is desirable for bales to maintain a cylindrical shape, however this has been especially difficult near the edge of the cylindrical bale. It is difficult for twine to remain on the edge of the bale as well as mechanically placing the twine in that position. Recently attempts have been made to extend a portion of the netwrap around the edge of the round bale. By allowing a slight portion of the netwrap to extend over the edge of the bale, the appearance of the round bale is improved. Furthermore, the bale is afforded additional protection. These methods have not been entirely successful as the prior art illustrates various deficiencies.
U.S. Pat. Nos. 5,230,193 and 5,243,806 illustrate a conventional fixed/variable hybrid baling chamber. To ensure that the core of the round bale is well defined, a sledge assembly is initially used to compress the crop material. As more crop material is introduced into the baling chamber, the apron of belts is loosened allowing more material to enter the baling chamber. The crop material remains compressed and in a cylindrical shape because of the interaction between the sledge assembly and belt apron. While this approach allows for the creation of a superior shaped and dense round bale, there are greater complications when encircling the bale with the netwrap material. Specially, the netwrap needs to be timed to enter the confines of the baling chamber through the sledge assembly and without interfering with operation of the apron of belts.
U.S. Pat. Nos. 4,366,665; 4,709,125; 4,969,315; 5,090,182; 5,103,621 and 5,311,729 illustrate various designs for wrapping round bales with either netwrap or silage wrap. Typically, the wrap only covers the cylindrical portion of the round bale and not the ends. Usually, the wrap is spread to cover the length of the cylindrical portion of the round bale by a series of idler and spreader rolls. The wrapping material is kept on a roll at a single location for dispensing.
U.S. Pat. Nos. 4,917,008 and 6,006,504 illustrate attempts to extend netwrap over the edge of the cylindrical bale, but on variable sized bale chambers. The baling chambers on these balers are less complex and do not form crop material into cylindrical bales as effectively as a variable/fixed hybrid baling chamber. This is reflected in the simplistic design of the netwrap delivery assemblies. U.S. Pat. No. 6,006,504 uses a pair of guide plates to compress the ends of the bale so as to be able to insert netwrap around the edge of the bale from the rear tailgate. The addition of the guide plates to compress the bale causes additional stresses to the sides of the baling chamber and could also distort the appearance and shape of the bale. U.S. Pat. No. 4,917,008 uses a netwrap that contains an elastic material to wrap around the edge of the cylindrical bale.
EP 1,264,533 discloses an improved netwrap delivery assembly for use on a variable/fixed baling chamber that permits the netwrap to extend around the edge of the cylindrical bale. The baler of the latter patent comprises a so-called duck bill that inserts the wrapping material between the adjacent rolls of the baling chamber. Though some balers are taught in the prior art which provide edge wrapping, and other balers are known which wrap only the cylindrical perimeter of the bales, no baler has hitherto offered the operator the ability to select the manner in which the bales are wrapped. The only way of preventing edge wrapping from taking place in balers of the first type would have been to fit a supply roll of a size not wide enough to the stretched over the edges of the bales.